Background information German Patent No. 19 530 736 describes a micromechanical acceleration sensor, and a method for manufacturing that acceleration sensor, in which a movable element is produced on a sacrificial layer, and the sacrificial layer beneath the movable element is removed in a subsequent step. The movable element is joined by deflection springs to joining regions, the sacrificial layer beneath the joining regions not being removed. The joining regions are thus joined immovably to a substrate. No features are disclosed with which adhesion of the movable elements is reduced.
The method and the micromechanical component according to the present invention have, in contrast, the advantage that because of the superficial protective layer, the adhesion tendency of the movable elements is reduced. It is therefore possible for the movable elements to be deflected by large forces to such an extent that they come into contact with other movable elements or with rigid elements, with no risk that the movable elements will thereby stick to one another or to the rigid elements. The operating reliability of the micromechanical components is improved by this feature. In addition, the structures thus formed can more easily be manipulated during manufacture, since there is no risk of adhesion.
The component itself is advantageously constituted from silicon, since this material exhibits very good mechanical properties and can very easily be patterned. A sacrificial layer of silicon oxide can be very easily etched, and silicon as a substrate material exhibits a very low coefficient of thermal expansion, which moreover is optimally adapted to the coefficient of expansion of a movable element made of silicon. Production of the protective layer is accomplished particularly easily by chemical vapor deposition or plasma-enhanced chemical vapor deposition.